Waiter thomas clifeobd-eaef



W. T. CLIF FORD-EARP.

RUBBER TIRE. v

APPUCATION FILED APILZB, 1920.

,7 5; Patented Nov. 22, 1921.

A s e \1 RUBBER TIRE.

Specification of Letters Patent.

Patented N (W. 22, 1921.

Application filed April 26, 1920. Serial No. 376,736.

(GRANTED unnrn'rnarnovrsrons or THE Mr or MARCH 3, 1921, 41 STAT. n,1313.

To all whom it may concern: 7

Be it known that I, WALTER THOMAS GLIFFORD-EARP, a subject of the Kingof Great Britain, and resident of Barnes, in the county of Surrey,England, have invented certain new and useful Improvements in andRelating to Rubber Tires, (for which I have filed an application inGreat Britain April 9, 1919, Patent No. 143,359,) of which the followingis a specification. This invention relates to rubber tires of thatgeneral character where resiliency is obtained by constructing the tireof such a section that the walls of the tire, which embrace an airtightinternal channel, tend to thicken and become displaced under load.

Tires have been-constructed of gable section with the walls of thetire'molded upon metal rings adapted to be presented onto a metalbinding rim or a wheel periphery a thinrubber surfaceor liner beingapplied f to the metal to insure air tight connection with the bindingrim or wheel periphery.

The essential feature of my invention is to mold the tire int'egral'witha circumferentially divided ring so "that normally the half rings areseparatedbut where the tire is applied to a wheel-or it may be a bindingr1m- -under heavy pressure the half rings, and with them the'w'alls ofthe tire [are forced togetherand thematerial of the tire put incompressive stress "this action also closing u cavity the rub er beingso arranged that an the internal circumferential air tight joint isformed at the circumferential division of-the ring.

This arrangement, has the advantage that the necessary action ofpressing the tire on t0 the rim of'the wheel also results in theenergization or putting in stress of the rubber of the tire wherebyincreased resiliency is imparted to it. This will be understood when itis remembered that the act of closing the gap between the two ringstends to 'cause the tire to increase its diameter and circumferentialmeasurement, and as this'is not possible owing to the circumferentialrestraint consequent upon the tire being substantially inextensiblecircumferentially, the walls of the tire become compressed or *displacedparticularly adjacent the integral rings and energy is stored up, as itwere, in

the rubber which is thus normally under compression. a

A further feature of the invention consists of so designing the sectionof therubber that theload is transmitted from the outer tread to thewheel rim substantially through the center of the circumferentlal wallsunder all conditions of load, it

being essential to myinvention that the ma teri'al'of the tire bulgesoutwardly and not inwardly under load.

In accordance with the invention a thickness of highly vulcanized rubberis vulcanizedto and at the base of the softer body of rubber.

A tire thus formed consists of an undivided tread having twocircumferentialwalls proceeding from it and terminating in acircumferentially divided ring formlng circumferential rims. When thegap is closed by forcing the two rings togetheron to the rim of a wheel,the softer rubber located at the inner peripheral edges of'the ringscomes together and forms an air-tight o1nt, andthe rubber is energizedscribed with reference to the accompanying drawings in which:

Figure 1 is a transverse section of a molded tire before application toits carrying rim. 1

Fig. 2 is a transverse section through a wheel rim and tire.

Fig. 3 is a similar view to Fig. 1 but showing the relative dispositionsof the same under different loads.

Fig. ,4 is transverse section through a wheel and tire showing theapplication of the tire direction to the wheel rim without theintervention of a supplementary steel rim, and 1 Fig. 5 is a viewsimilar to Fig. 4 of a twin tire constructed in accordance with myinvention.

Referring now particularly to Figs. 1 and on a large radius as also arethevpoints of from Fig.2 of the drawing? when the tire is in position a2 a represents the main body of the tire which is composed of softrubber and b the two wall members'which may'be of highly vul' canized 0rhard rubber molded integral with the respective halves of a steel rim 0.The

walls of the tire embrace a circumferential channel-d substantially'ofthe section shown when the tire is fitted to the rim, which channel andthe rims c are circumferentially divided as at e. I H g The section ofthis channeld as also the section of-themain body of the tire'is ofgreat importance in assuring the attainment of the desired objectsbefore mentioned in the opening statement. As will be seen this channels its greatest width at the base, the increase continuing radually fromthe top or narrow side while 20 t e ints of mergencebetweenthe sidewalls of t e channel and its base are constituted by curves of largeradius. The objectof these curves is to lessen the resistanceto'deformation at these points with'the result that under load thesecorners become straightened out'until-they asumethe difl'erent positions indicated; roughly by dotted lines in Fig.3.- If the, load weresufliciently great these corners would collapse to: such an ex- 7 tentas to meet.

The top or normally narrow side of the channel issimilarly curved-but inthis case This configuration enables the toprside to readily exthe curveor curves are. smaller.

pand under compression: until the same. assumes one of theshaposset'forth in Fig.3. The tread of theme ic -domed or curved mergencebetween-such tread and the sides of the tire. This particularconfiguration of tread isof great importance when employed inconjunction with a channel'of a cross section substantially as specifiedabove.

The particular'advanta of this section of tread obtains when un or loadinasmuch as the tire then expands: outwardly ,atthe point of roadcontact until'the same assumes the different positions, depicted in Fig.3, e the degree of expansion depending of. course upon the extent of theload. A result of this particular section of tire is that the meandirection of greatest load is fromthe outer tread to the wheel rimsubstantially through the center .of the circumferential side wallsunder all conditions of load as is clearly demonstrated in Fig. 3 by thelines therein shown which are, indicative of the -circumferentialdivision 6 the cheeks f composed ofthe softer rubber project slightlydirection of the thrust through one side of the tire under variousloads.

To promote an air tight joint alongthe beyond the cheeks of the tworings or ring portions" b so that uponbeing forced .together as when inposition on the rim these abutment ofthe soft cheeks close uptightly'and thus constitute an air tight joint throughout the wholeextent of the division.

In Fig. 4 the tire as just described is shown fitted direct to the rimof the wheel Without the intervention of a supplementarymetal rim, thetwo partsfof therim beingheld together by any suitable means such asbolts or clamps, while in Fig. 5 a twin tire is-shown constructedaccordance with my invention. It will be seen that in this case thecircumferential ring is divided into three parts which whenbronghttogether form air tight joints-at the divisions -e'. The dottedlinesindicate the -approxi- .mate relative positions of the parts beforethe tire is forced on the wheel, or rim-and the full lines the positionafter the parts have been forced to ther as before :described. In thiscase.

eload will. be transmitted through the center; or-partition 'di- 1viding the two channels d and also through the circumferential sidewalls a reinforcing ring is indicated ate. In all formslof the inventioneach side wall has its greatest width at the base. or that portion whichen-- gages the rim and narrows progressively rom the base portion to thetread.

'What I claim and desire to secure byLetters Patent is 1. A solidrubbertire comprisinga' side walls separated by an internal recess, aninner circumferential wall member. having a circumferentialdivision,a-supportin inextensible 'member' integrally 1 associated I .with the;inner circumferential wall, jsaid support1ng inextensible memberalsohavinga circumferential division corresponding to thecircumferentialdivis'lon of the inner circumferential wall of the tireso that prior tothe .assembleiyerfor. use, the two ,parts [I of the inner circumentialwallaresop rated whereby when two parts of the inex .tial divisioncorrespondingto thejcircumferential division of theinner circumferentialwall of the tire and presenting cheeks,

said tire'having overhanging annular checks of soft rubber.projecting-slightly beyond the cheeks of the inextensibleiringmembersand adaptedrto mme -into abutmentwhen the tire is. assembled .in .thetire'carrying rim and, an air-tight joint is formed by the v overhanginannular cheeks, substantially as describe 3. A solid rubber tirecomprising treads, side walls, a central divisional wall, internalrecesses separating said sidewalls from said central divlslonal wall, anlnner ClI'CllmfGT- ential wall having circumferential divisions,

a supporting inextensible member into-c grally associated with the innercircumferential wall, said supporting inextensible member also havingcircumferential di- 10 visions corresponding to the circumferentialarated whereby when the parts of the inextensible member are caused toapproach each other the material of the tire is put in compressivestress and aiiitight joints are formed substantially as described.

In witness whereof I afiix my signature.

WALTER THOMAS CLIFFORD-HARP.

